Polymeric quaternary ammonium polytungstates



Patented June 1, 1954 POLYMERIC QUATERNARY AMlVIONIUM POLYTUNGSTATESWilliam 0. Forshey, Jr., New Castle, and James E. Kirby, Wilmington,Del., assignors to E. I. du Pont de Nemours & Company, Wilmington, Del.,a corporation of Delaware No Drawing. Application February 23,1952,Serial No. 273,146

27 Claims. I

This. invention relates to new addition polyusers and copolymers.

The advent of new synthetic fibers and films has been attended by manyadvantages but has also occasioned new problems. For instance,acrylonitrile polymers are outstanding in many applications because oftheir inertness but this same inertness has rendered difiicult theirprocessing in extended form, i. e., in film or fiber form, particularlywhen the processing involves conventional aqueous treatments. Otheraddition polymers have to some extent the same disadvantage. Thus, thedyeing of acrylonitrile homopolymer fibers is attended with considerabledifiiculty.

U. S. Patent 2,491,471 discloses a solution,

albeit not a complete one, of this difficulty. This patent disclosesthat copolymers of acrylonitrile with small proportions of thevinylpyridines are readily dyeable and can be processed by the normallyused aqueous processing treatments in the film, and particularly thefiber industries. In contrast, the corresponding acrylonitrilehomopolymer is difficultly dyeable and not readily handleable by thenormal processing treatments. ridine copolymers, although more amenableto the usual dyeing and processing conditions, do not exhibit thedesirable, high thermal insensitivity of the acrylonitrile homopolymers.

Another solution, still not a complete one, is disclosed in thecopending application of Barney, Ser. No. 216,838, filed March 21, 1951.This discloses that copolymers of acrylonitrile with certain simplevinylidene quaternary ammonium compounds are readily dyeable andhandleable in aqueous systems but exhibit an inertness somewhat lessthan that of acrylonitrile homopolymers. Thus, even these desirableccpolymers do .not exhibit the outstanding thermal insensitivity of theacrylonitrile homopolymers.

U. S. Patents 2,572,560 and 2,572,561 disclose copolymers ofacrylonitrile with vinyl and allyl esters containing quaternary ammoniumhalide, groups.

Other polymers having recurring extralinearsensitivities which alsoexhibit adequate response to aqueous processing treatments. Anotherobject is the preparation of acrylonitrile copolymers. Alfurther objectis the preparation of new However, these acrylonitrile/vinylpypolymers.Another object is the provision of a new treatment process for polymersin extended form. Other objects will appear hereinafter.

These objects are accomplished by the present invention of resinousaddition polymers having a wholly carbon polymer chain and containingextralinear quaternary ammonium polytungstate groups, 1. e., resinousaddition polymers having extralinear quaternary ammonium nitrogensbonded to a polytungstate anion, of a process therefor wherein aresinous addition polymer containing extralinear quaternary ammoniumsalt groups, the salt being of a simple acid, are reacted with a solublepolytungstate whereby the salt of the polytungstic acid with thequaternary ammonium polymer is formed. These polymers are readilyd-yeable and handleable by normally used aqueous processing treatmentsand at the same time are quite low in thermal sensitivity. In this newclass of polymers the quaternary ammonuim polytungstate groups arepresent as extralinear components on and not in the polymer chain.

A particularly preferred class of this polymeric extralinear quaternaryammonium polytungstates are those wherein the quaternary ammoniumnitrogen of the cation of the polytungstate is bonded, either directlyor mediately, through a negative, i. e., electron-attractive group(including nuclear carbon of an aromatic heterocyclic ring), to thepolymer chain.

In the quaternary ammonuim polytungstates of this invention the Valencesof the quaternary ammonium nitrogen not bonded as above to the polymerchain or to the polytungstate anion are satisfied by hydrocarbonradicals whose free valences' are all attached to the quaternaryammonium nitrogen. Thus a divalent radical has both of its valencesjoined to the nitrogen forming therewith a heterocyclic ring.

The most readily available" and therefore more important classes'ofquaternary ammonium polytungstates of this invention are those whereinrecurring extraline'ar quaternary pyridinium polytungstategroups,hydrocarbon except for the polytungstate anion and the pyridiniumnitrogen, are joined to the polymer chain by carbon of the pyridiniumring and those wherein recurring extralinear quaternary ammoniumpolytungstate groups are bonded from the nitrogen to the alkylene, R,radical of a group --[CO]nOR-, wherein n is a cardinal number notgreater than one, and thence to the polymer chain, the extralinearquaternary ammonium substituent on the polymer chain being hydrocarbonexcept for the nitrogen, the polytungstate anion and the [COlnO- group.The polymers may also contain similar quaternary ammonium polymer unitswith however the nitrogen bonded ionically to the anion of a simplemono-, di-, or tribasic acid, organic or inorganic, rather than to theanion of the complex polytungstic acid.

In the new polymers of this invention the quaternary ammoniumpolyt-ungstate groups are extralinear components on rather than in thepolymer chain, with the quaternary nitrogens of the polytungstate groupbonded directly through a hydrocarbon chain or a hydrocarbon chaininterrupted by an oxy (ether or ester) group to the wholly carbon chainof the polymer with the remaining valences of the quaternary nitrogensatisfied by monovalent hydrocarbon radicals. The radicals bonded to theextralinear quaternary ammonium nitrogen as Well as the one joining thequaternary ammonium nitrogen to the main polymer chain are free ofaliphatic unsaturation. The characteristic recurring units of the newpolymers of this invention are conviently represented in combined formby the following structural formula wherein R is hydrogen or amonovalent hydrocarbon radical free from aliphatic unsaturation andpreferably saturated aliphatic hydrocarbon of no more than four carbons,i. e., lower alkyl hydrocarbon, and n and m are cardinal numbers nogreater than 1 and may be alike or different with the single indicatedterminal free valence on the group being bonded through a hydrocarbonchain free from aliphatic unsaturation to a quaternary ammonium nitrogenatom, one valence of which is singly ionically bonded to the anion of apolytungstic acid, the remaining valences of the said quaternaryammonium nitrogen being satisfied by monovalent hydrocarbon radicalsfree of aliphatic unsaturation and usually of no more than six carbonsapiece, any two of which can be together joined to form with thequaternary ammonium nitrogen a heterocycle, and m is used to indicatethe degree of polymerization. The preferred polymers of this inventionwill contain in combined form such recurring units wherein n and m areas given above, R is hydrogen or a short-chain, saturated aliphatichydrocarbon radical, i. e., lower alkyl of from 1 to 4 carbons, and theindicated free valence of the group is directly bonded through a singlehydrocarbon radical of from 2 to 6 carbons, free of both Zerewitinoffactive hydrogen and aliphatic unsaturation and of at least two carbonsbetween the free valences, and most preferably a saturated hydrocarbonradical of from 2 to 6 carbons, to a quaternary ammonium nitrogen atom,one valence of which is singly bonded ionically in multiples of one tosix, usually one to three, to the anion of a polytungstic acid with theremaining valences of the said quaternary ammonium nitrogen beingsatisfied by monovalent hydrocarbon radicals free from aliphaticunsaturation and of no more than eight carbons apiece, and mostpreferably by saturated aliphatic, hydrocarbon radicals of no more thanfour carbons apiece, any two of which can be together joined to formwith the said quaternary ammonium nitrogen atom a saturated nitrogenheterocycle, i. e., a piperdyl heterocycle.

The polymeric quaternary ammonium polytungstates of this invention notonly include those polymers wherein each combined unit contains anextralinear quaternary ammonium nitrogen, bonded as previously describedin m-ultiples of from one to six to polytungstic acid anions, but alsothose which contain in combined form, in addition to the recurringquaternary ammonium polytungstate units, units of other additionpolymerizable monomers, e. g., the mono and diene monomers. For the moreimportant uses the polymer should be wholly of monoethenoid monomers, i.e., monomers having but one aliphatic unsaturation and that ethylenicand preferably terminally ethylenic. To attain the relatively highthermal stability evidenced by this new class of polymers, there must bepresent in the polymer chain at least 0.023% and preferably at least0.15% by weight of the polymer of units containing the extralinearquaternary ammonium polytungstate anions, i. e., the polymers of thisinvention must contain at least 0.015% and preferably at least 0.1%combined tungsten by weight.

The following examples in which parts are by weight are illustrative ofthe invention In these examples the inherent viscosity data given areobtained at 25 C. with dimethylformamide solutions of the polymerinvolved at a concentration of 0.2 g. of polymer per cc. of solution.

EXAMPLEI A. Preparation of 1,Z-dimethyl-5-vinylpyridiniump-toluenesulfonate A mixture of 23.8 parts of 2-methyl-5-vinylpyridineand 37.2 parts of methyl p-toluenesulfonate is dissolved in 51.5 partsof acetone and the resulting solution allowed to stand overnight at roomtemperature. The white crystalline product thus obtained is removed byfiltration, washed well with anhydrous ether, and dried under reducedpressure. There is thus obtained 45 parts of1,2-dimethyl-5-vinylpyridinium p-toluenesulfonate. This product, afterrecrystallization from a 1:2 by volume mixture of ethanol and ethylacetate, exhibits a melting point of 142 C.

B. Preparation of an acryZonitriZe/LZ-dz'methyl- 5-oinylpyridz'nz'ump-toluenesulfonate copolymer A solution of 6.29 parts of potassium indihydrogen phosphate in 3500 parts of distilled water in a reactionvessel fitted for eflioient agitation is adjusted to pH 7.0 by theaddition of 0.5 N-aqueous sodium hydroxide solution. To this solution isadded 240 parts of freshly distilled acrylonitrile, 12.65 parts of1,2-dimethyl-5- vinylpyridinium p-toluenesulfonate and 3.48 parts ofthiourea. The temperature of the mixture is then adjusted to 25 C. and104.5 parts of fresh 3% aqueous hydrgen peroxide is added under anatmosphere of nitrogen and the resulting mixture then agitated for threehours while maintaining the temperature at 25 C. The resulting whitesolid is removed from the polymerization mixture by filtration andwashed well with distilled water, then with methanol containing about0.4% 1')..- toluenesulfonic acid, and finally with excessphosphotungstate at pH=2.35.

methanol, all while on the filter. After drying under reduced pressureat 60 C. there" is thus obtained 165 parts of a 95/5 acrylonitrile/l,2-dimethyl 5 vinylpyridinum p-toluenesulfonate -copolymer exhibiting aninherent viscosity of 2.01.

C. Preparation of acryZonitriZe/LZ-dimethyl-5- m'nylpyridinium ptoZuenesaZfonate/1,2 dz methyl 5 cinylpyridinium phosphotangstatecopolymers A self-supporting film of the 95/5 acrylonitrile/1,2-dimethyl-5-vinylpyridinium p-toluenesulfonate copolymer describedabove in part B is prepared by solvent casting fromdimethylfcrrcasolution. A sample of this film is boiled for onehalf hourin a 1% aqueous solution of sodium The resulting quternary copolymercontaining combined acrylonitrile, 1,2-dimethyl-5-vinylpyridiniump-toluenesulfonate and l,2-diniethyl-5-vinylpyridinium phosphotungstateunits exhibits excellent-then mal stability after soap washes. Forinstance, samples of this film after boiling in 0.5 aqueous soapsolution for hour remain water-white with no evidence of thermaldecomposition after baking at 165 C. for 20 minutes. In contrast,samples of the starting acry1onitrile/1,2-dimethyl-5-vinylpyridiniump-toluenesulfonate copolymer turned dark orange-brown under the sameconditions.

Another film sample of the starting 95/5 acrylonitrile/1,2dimethyl-B-Vinylpyridinium p-toluenesulfonate copolymer is boiled forhour in an aqueous phosphotungstic acid solution the pH of which hasbeen adjusted from the original 0.9 to 2.0 by the addition of aqueoussodium hydroxide. There is thus obtained a 94.0/4.6/l.4=acrylonitrile/1,2-dimethyl-5-vinylpyridinium ptoluenesulfonate/ 1 ,2-dimethyl-5 -vinylpyridinium phosphotungstate oopolymer which exhibitssimilar excellent thermal resistivity, remaining waterwhite after bakingat 165 C. for twenty minutes subsequent to a A; hour boil in 0.5%aqueous soap solution.

2 [P W12 0 405 L or the dimer t LP {W24 0 505G501 Another film sample ofthe starting /5 acrylonitrile/l,2-dimethyl-fi-vinylpyridiniumptoluenesulfonate copolymer boiled for one minute in an aqueous 10%phosphotungstic acid solution at pH 2.0. ternary copolymer is found byanalysis to contain 0.018% tungsten, i. e., the product is a94.981/4,.992/0.027 acrylonitrile/1,2-dimethyl-5-; vinylpyridinium ptoluenesulfonate/1,2 dimethyl-S-vinylpyridinium phosphotungstate co-After washing and drying the polymer. After boiling for A hour inaqueous 0.5% soap solution followed by baking for 20 minutes at 165 C. afilm of this copolymer exhibited some evidence of thermal decomposition,being light yellow in color, but appreciably less so than a film of thestarting two component copolymer which under like conditions turns adark orange-brown.

fit!

D. Preparation of dyed ternary copolymer films by after-treatment 0starting binary quaternary polymers Film samples of the 95/5acrylonitrile/1,2- dimethyl 5 vinylpyridinium p-toluenesulfonatecopolymer described previously in Example I, part B are dyed by boilingfor half an hour in various dye baths made up from 1,000 parts ofdistilled water adjusted to pH 6.0 with dilute acetic acid and two partsof representative dyes including a blue anthraquinone dye whoserecognized foreign prototype is Alizarin Supra Blue A, a violetanthraquinone dye of Colour Index No. (CIN) 1030, and an orange acid dyeof CIN 161. The deeply d ed film samples are then heated at the boil forten minutes in a 10% aqueous phosphotungstic acid solution adjusted topI-I 2.0 with dilute aqueous sodium hydroxide. The dyed ternaryacrylonitrile/ 1,2-dimethyl-5-Viny1pyridinium p-toluenesulfonate/ 1,2dimethyl-5-vinylpyridinium phosphotungstate copolymer films are thenboiled for half an hour in 0.5 aqueous soap solution, during whichprocess essentially no color is removed. Baking of the washed films fortwenty minutes at C. gives no evidence of thermal decomposition. Thedyed films retain their initial shades.

In contrast, samples of the starting 95/5acrylonitrile/1,2-dimethyl-5-vinylpyridinium p-toluenesulfonatecopolymers, when dyed in the same dye baths and soaped and baked in thesame fashion, all give evidence of deepseated thermal decomposition,with the shades in all instances being appreciably darkened and in somecases completely changed, for instance the blue dyed films turn green.

A film sample of the three component copolyrner containing only 0.018%tungsten described above in Example I, Part C when dyed in the mannergiven above with the blue anthraquinone dye is dyed a fast, deep blue.After being boiled for half an hour in aqueous 0.5% soap solution andthen baked at 165 C. for twenty minutes the dyed film exhibits noevidence of thermal decomposition, the blue shade remaining unchanged.In contrast, as pointed out previously, samples of the original twocomponent copolymer similarly treated show clear evidence of deep seatedthermal decomposition.

EDKAIIIPLE II Preparation of an acryZonitriZe/i,2-dirnethyZ-5-vinylpyridinium p toZaenesuZfonate/Z ,2 dimethyl-5-vinylpyridiniamtungstate dilute hydrochloric acid. The treated film is removed from thepolytungstic acid solution and dried, and subsequently boiled in 0.5%aqueous soap solution for half an hour. .The film, after being baked at165 C. for twenty minutes, still remains'water-clear, with no signs ofthermal decomposition. In contrast, a control film of the startingtwo-component copolymer turns deep orange-brown in the baking cycleafter the soap wash. Other experiments similarly carried out show thatthe quaternary tungstate copolymers can be readily prepared by similartreatments at any pH below 3.0, with the preferred pH range being from1.5 to 2.5.

EXAMPLE III A. Preparation of cmacrylonitrz'Ze/Z-vinylomyethyltrz'methylammonium chloride copolymer Thiscopolymer is prepared in exactly the same manner as that described inExample I, part B, substituting 2-vinyloxyethyltrimethylammoniurnchloride for the 1,2-dimethyl-5-vinylpyridinium p-toluenesulfonate usedthere and using only half the quantities of thiourea and hydrogenperoxide. There is thus obtained 207 parts of a 95/5acrylonitrile/Z-vinyloxyethyltrimethylainmonium chloride copolymerexhibiting an inherent viscosity of 2.44.

B. Preparation of an acryZomtriZe/Z-vinyloa:yethyZtrimethylammoniumchZoride/Z-vinyloxyethyltrz'methylammonium phosphotungstate co polymer Asample of the 95/5 acrylonitrile/2-vinyloxyethyltrimethylammoniumchloride copolymer described above in Example III, part A is prepared infilm form by solvent casting from di- The strong, clear,

methylformamide solution. self-supporting film thus obtained is boiledfor ten minutes in a aqueous solution of phosphotungstic acid with thepH adjusted to 1.8 by addition of dilute sodium hydroxide solution. Thefilm of the acrylonitrile/2-vinyloxyethyltri methylammonium chloride/2vinyloxyethyltrimethylammonium phosphotungstate copolymer thus obtainedafter boiling for half an hour in an aqueous 0.5% soap solution exhibitsno sign of thermal decomposition after twenty minutes at 165 C. Incontrast, a film of the starting 95/5 acrylonitrile/2vinyloxyethyltrimethylammonium chloride copolymer turns deep orangebrownwhen subjected to the same wash and bake cycle.

EXAMPLE IV A. Preparation of beta-methacrylyloryethyltrimethg/Zammonimnp-toZue-nesulfonate To a cooled (ice/ water bath) solution of freshlydistilled dimethylaminoethyl methacrylate in 71A parts of anhydrousether is added slowly under anhydrous conditions a solution of 18.6parts of methyl p-toluenesulfonate in 28.5 parts of anhydrous ether. Thereaction mixture is allowed to stand at approximately 4 C. for four daysunder anhydrous conditions in an atmosphere of nitrogen. The resultingwhite, crystalline solid. thus obtained is removed by filtration underanhydrous conditions and dried under reduced pressure at roomtemperature. There is thus obtained 26.6 parts ofbeta-methacrylyloxyethyltrimethylammonium p-toluenesulfonate.

B. Preparation 0; an amyZom'triZe/beta-methacryZyZomyethyZtrimethglammonium p toluenesulfonate copolymer lhis copolymer is prepared asdescribed previously in Example I, part B, substituting 12.0 parts ofthe above-described beta-methacrylyloxyethyltrimethylammoniump-toluenesulfonate for the 12.65 parts of 1,2 dimethyl-5-vinylpyridiniump-toluenesulfonate. There is thus obtained 153 parts of a 95.2/4.8acrylonitrile/betamethacrylyloxyethyltrimethylammoniump-toluenesulfonate copolymer as a white powder exhibiting an inherentviscosity of 2.05.

C. Preparation of anacrylonitrile/beta-methacrylyloazyethyltrimethylammonium ptoluenesuZfonate/beta methacrylyloccyethyltri methylammoniumphosphotungstate copoly- 'mer A sample of the 952/413acrylonitrile/betamethacrylyloxyethyltrimethylammoniump-toluenesulfonate copolymer described above in Example IV, part B issolvent cast from dimethylformamide solution to give a clear, strong,selfsupporting film. A sample of this film is heated for ten minutes atthe boil in a 10% aqueous phosphotungstic acid solution with the pHadjusted to 2.0 by the addition of aqueous sodium hydroxide solution.The ternary copolymer film thus obtained, after washing and drying, isfound to contain 1.06% tungsten. This indicates that the ternarycopolymer is a 9 12/42/16 acrylonitrile/betamethacrylyloxyethyltrimethylammonium ptoluenesulfonate/beta-methacrylyl- 0Xyethyltrimethylammoniumphosphotungstate copolymer. Film samples of this copolymer, afterboiling for half an hour in an aqueous 0.5% soap solution, exhibit nothermal decomposition when heated for twenty minutes at 165 C. Incontrast, a film of the starting 952/43 acrylonitrile/betamethacrylyloxyethyltrimethylammonium p-toluenesul'fonate copolymer turnsdark orange-brown when subjected to the same treatment.

A sample of this ternary copolymer film is boiled for one and one-halfhours in a solution of 0.2 part of a blue anthraquinone dye whoserecognized foreign prototype is Alizarin Supra Blue A. in parts ofdistilled water adjusted to pH 6.0 with acetic acid. At the end of thisdyeing cycle the film is richly colored a deep blue. The dyed film isboiled for half an hour in an aqueous 0.5% soap solution, during whichtime very little, if any, of the color is washed out. This dyed andwashed film sample gives no evidence of thermal decomposition afterbeing heated at C. for twenty minutes. In contrast, samples of thecontrol 952/413 acrylonitrile/betamethacrylyloxyethyltrimethylainmoniump-toluenesulfonate copolymer, although dyeing to deep, fast shades,after undergoing the same wash and baking cycle are dark green-blue withevidence of thermal decomposition.

Similar results are obtained with another sample of this same type threecomponent copolymer prepared by treating another film sample of the952/43 acrylonitrile/beta-methacrylyl- 0Xyethyltrimethylammonium ptoluenesulfonate copolymer for only three minutes at the boil with anaqueous 10% phosphotungstic acid solution at pH 2.0. The three componentquaternary copolymer thus obtained, after washing and drying, is foundby analysis to contain 0.46% tungstem, from which it is calculated thatthe ternary copolymer is a 9413/45/07acrylonitrile/betamethacrylyloxyethyltrimethylammoniump-toluenesulfonate/ beta methacrylyloxyethyltrimethylammoniumphosphotungstate copolymer.

A film sample of this copolymer is easily dyed in half an hour at theboil to a deep blue shade using a dye bath containing 0.2 part of thepreviously mentioned blue anthraquinone dye in a solution of parts ofammonium acetate in 100 parts of water with the pH adjusted to 6.0 withacetic acid and then to 3.0 with hydrochloric acid. This dyed film showsno color change or other evidence of thermal decomposition when bakedfor twenty minutes at 165 C. after having been soaped for half an hourat the boil in an 0.5% aqueous soap solution. In contrast, film samplesof the starting two component copolymer turn dark blue-green whensimilarly soaped and baked after having been dyed. This copolymercontaining the lower percentage of combined tungsten (0.46%) seems asstable thermally as the one described earlier in this example containingthe higher percentage of combined tungsten (1.06%) and furthermore ismore easily dyed. See also Example I, part 0. Copolymers containing suchlower percentages of combined tungsten, e. g., from as low as 0.05 to0.75% tungsten are preferred.

EXAlt/IPLE V Preparation of anacryZonitriZe/beta-methacrylyloxyethyltrimethylammoniump-tolnenesnlfonate/beta methacrylylozryethyltrimethyl ammoniumsiZicotu-ngs-tate copolymer A sam le of the 952/48acrylonitrile/betamethacrylyloxyethyltrimethylammoniump-toluenesulfonate copolymer described above in Example IV, part B, isobtained in film form by solvent casting from dimethylformamidesolution. The clear, strong, self-supporting film thus obtained isheated for ten minutes at the boil in a 10% aqueous silicotungstic acidsolution with the pH adjusted to 0.5 by the addition of a small amountof concentrated hydrochloric acid. The acrylonitrile/betamethacrylyloxyethyltrimeth ylammonium p toluenesulfonate/betamethacrylyloxyethyltrimethylammonium silicotungstate copolymer thusobtained, after boiling for half an hour in 0.5% soap solution, gives noevidence of thermal decomposition after heating for twenty minutes at165 C. In contrast, a film sample of the startingacrylonitrile/beta-methacrylyloxyethyltrimethylammonium ptoluenesulfonate copolymer turns deep orange-brown when subjected to thesame wash and bake.

EXAMPLE VI A. Preparation of poly bet-methacrylyloxyethyltrimethylammonium methylsulfate A solution of 167parts of freshly redistilled beta-dimethylaminoethyl parts of methylethyl ketone is added with vigorous stirring over a period of one hourat ice bath temperature to a solution of 126 parts of freshlyredistilled dimethyl sulfate in 800 parts of methyl ethyl ketone. Theresultant reaction mixture is allowed to stand in an ice/water bathovernight and the solid white crystalline product removed by filtrationand dried under reduced pressure. There is thus obtained 260 parts (92%of theory) of beta-methacrylyloxyethyltrimethylammonium methylsulfate.This monomer is dissolved in 1500 parts of distilled water at 60 C.under an atmosphere of nitrogen and one part of alpha,-alpha-azobis(isobutyramidine hydrochloride) is added with stirring. Thesolution becomes viscous in about fifteen minutes and the polymerizationis continued at 60 C. for five hours. The resultant polymer solution isevaporated to dryness in an oven at 90 C. and the glassy polymer thusobtained then pulverized with water methacrylate in 200 5 .10 in ahigh-speed mechanical stirrer, isolated by filtration and redried. Thereis thus obtained 240 parts (about conversion) ofbetamethacrylyloxyethyltrimethylammonium methylsulfate polymer.

B. Preparation of poly beta methacrylylowyethyltrimei'hyZammoniumphosphot-ungstate To a freshly filtered solution of ten parts of theabove-described poly-betamethacrylyloxyethyltrimethylammoniummethylsulfate in about 300 parts of distilled Water is added a solutionof 56.5 parts (about 1.5 molar proportions based on the quaternarymethylsulfate polymer) of phosphotungstic acid (molecular weight 6160)in about 500 cc. of distilled water. A white solid product separates atonce and is removed by suction filtration and washed on the filter withexcess water. After drying under reduced pressure in the presence ofanhydrous phosphorus pentoxide, there is thus obtained 36.2 parts (aboutof theory) of poly-beta-"nethacryly1oxyethyltrimethylammoniumphosphotungstate as a white powdery solid.

Analysis Calculated for C27H54O4GN3PW122H2O'2 N, 1.227%;

Calculated for C27H54O4eN3PW1a3I-I2O: N, 1.22%;

Found: N, 1.18%, 1.15%; W, 64.04%, 64.48%.

EXAMPLE VII A. Preparation of a vinylacetate/beta-methacrylyloxyethyltrimethylammonium methylsuZfatecopolymer A polymerization reactor is charged with 16 parts of vinylacetate, 1' parts of beta-methacrylyloxyethyltrimethylammoniun1methylsulfate, about 85 parts of tertiary butanol, and 0.2 part ofalpha,alpha'azodiisobutyronitrile. The polymerization mixture heated at60 C. for ten hours under an atmosphere of nitrogen. After removin thetertiary butanol by distillation under reduced pressure, there is thusobtained 18.1 parts of an 80/20 vinylacetate/beta-methacrylyloxyethyltrimethylammonium methylsulfatecopolymer as a fibrous, slightly hydroscopic, amorphous powder solublein methanol from which solution self-supporting films can be solventcast. The copolymer exhibits in this solvent an inherent viscosity of1.62 at a concentration of 0.2 part of polymer per cc. of solution at 25C.

Analysis Calculated for 80% C4HeO2/20% ClOI'IZlOGSNI N, 0.99%. Found: N,0.98%.

B. Preparation of a vinylacetate/beta-m'ethacrylylozcyethyltrimethylammoninm phosphotungstatecopolymer To a solution of 3.5 parts of the above-described 80/ 20 vinylacetate/betamethacrylyloxyethyltrimethylammonium methylsulfate copolymerin about 75 parts of C. P. methanol is added with stirring a solution offour parts (about 1.5 molar proportion based on the quaternarymethylsulfate copolymer) of phosphotungstic acid in about 7.5 parts ofC. P. methanol. A small amount of white solid precipitates at once.Approximately 75% of the methanol is removed from the reaction mixtureby distillation under reduced pressure and approximately 100 parts ofdistilled water then added. The White solid product thereby obtained isseparated by centrifuging, washed thoroughly with excess water andfinally separated again in a centrifuge. After drying there is thusobtained 1.8 parts (about 50% lost by spillage) of a vinylacetate/betamethacrylyloxyethyltrimethylammonium phosphotungstatecopolymer as an off-white powder from which heatand wash-stable,self-supporting films can be cast.

The present invention is generic to addition polymers, includingcopolymers, having a wholly carbon polymer chain and containingrecurring extralinear quaternary ammonium polytungstate groups. In thenew polymers of this invention the quaternary ammonium nitrogen isionically bonded to the polytungstic acid anion, is bonded to the carbonchain of the polymer through a negative, i. e., electronegative, i. e.,electronattractive group, including nuclear carbon of an aromatic ring,and has a remaining valence bonded to the positive organic radical,usually alkyl, of a quaternizing agent. The extralinear quaternaryammonium polytungstate substituent contains only carbon, hydrogen,oxygen, the quaternary nitrogen, and the metals of the polytungstateanion.

Preferred polymers are those wherein the recurring quaternary ammoniumnitrogens are a) those of an N-alkylpyridinium nucleus, hydrocarbonexcept for the pyridinium nitrogen and bonded from ring carbon directlyto the polymer chain, and b) those wherein a trialkylammonium nitrogenis bonded through the alkylene, -R,, radical of a group RO[CO]n-, wheren is a cardinal number not greater than one, to the polymer chain. Thepolymers of the present invention all contain a plurality of recurringextralinear quaternary ammonium polytungstate groups with one valence ofeach of the nitrogens of said groups bonded to the main polymer chainthrough a multiply bonded carbon, including the carbons of an aromaticring such as the pyridinium ring or through, either directly ormediately, an ether oxygen or an ester linkage, either as a carbonyloxyor oxycarbonyl linkage.

The extralinear quaternary ammonium nitrogens each have a valenceionically bonded singly in multiples of from one to six to the anion ofa polytungstic acid. The remaining three valences of each of thequaternary nitrogens in the extralinear quaternary ammoniumpolytungstate units are satisfied by organic radicals, preferablyhydrocarbon radicals, of one to eight carbons, with usually at least twoof said three valences being satisfied by hydrocarbon radicals of one toeight carbons, which may be together joined to form with the saidquaternary ammonium nitrogen a ring. Generally these said three valencesof the extralinear quaternary ammonium nitrogens will be satisfied bysolely hydrocarbon radicals having a total of three to twelve carbonsand preferably saturated aliphatic hydrocarbon radicals of a total offrom three to nine carbons, with the lower (one to two carbon) saturatedaliphatic hydrocarbon radicals being particularly useful. Particularlyuseful are the polymers wherein the nitrogen is bonded to thepolytungstate ion, to the polymer chain through a) an oxyalkyleneradical or b) a carboxyalkylene radical, or DV- ridinium ring carbon,any remaining valences of the nitrogen being satisfied by alkyl radicalsof up to four carbons. Thus, the recurring quaternary ammoniumpolytungstate nitrogens can be joined to the CnI-Iai radical of a (CO)mOCnH2Jzgroup wherein m is a cardinal number not greater than 1 and n isan integer from one to six, the other valences oi the nitrogen beingsatisfied by monovalent hydrocarbon radicals of a total of three totwelve carbons. In the remaining class the quaternary nitrogen is thatof an N-alkylpyridinium nucleus, hydrocarbon except for the nitrogen andbonded from carbon of the nucleus to carbon of the wholly carbon polymerchain.

The polymeric extralinear quaternary ammonium polytungstates of thisinvention, wherein in each instance the extralinear quaternary nitrogensare bonded as described previously to a polytungstic acid anion, includethose polymers wherein the extralinear quaternary nitrogen is bonded tothe main polymer chain through a carbon free of aliphatic unsaturationbut carrying a multiple linkage, including an aromatic ring linkage, e.g., where the extralinear quaternary radical is the N-methylpyridiniumradical; those polymers wherein the extralinear quaternary nitrogen isbonded to the main polymer chain through an ether linkage, e. g., wherethe'extralinear quaternary radical is thedimethylcycloheXylammoniumethyloxy radical; and those polymers whereinthe extralinear quaternary nitrogen is bonded to the main polymer chainthrough an ester linkage including both an oxycarbonyl and a carbonyloxylinkage, e. g., where the extralinear quaternary ammonium radicals arethe diethylbenzylammoniumethyloxycarbonyl radical or thetrimethylammoniumethylcarbonyloxy radical.

The polytungstic acids which form the anions of the combined quaternaryammonium polytungstate units in the polymers of the present inventioninclude both the isopolyand the heteropolytungstic acids. Thesepolytungstic acids, like other weak acids formed from the amphotericmetals of groups V-A and VI-A of the periodic table, are characterizedby the ease with which they condense to form anions containing severalacid anhydride molecules. Condensed acids containing only one type ofacid anhydride are known as the isopoly acids, in the present instanceisopolytungstic acid. Condensed acids containing acid anhydrides of twoacid forming metals are termed heteropolyacids, in the present instancethe heteropolytungstic acids, wherein usually only one molecule of theother acid anhydride is involved, which, see Ephraim-Anorganische Chemie(Steinkopf, Dresden, 1934-) page 426 et seq, furnishes the central atomor central anion of the whole complex anion. While elements of all eightgroups of the periodic table have been reported as capable of furnishingvarious acid anhydride molecules to serve as the central ion in theformation of a complex heteroacid anion, the present invention isprimarily concerned, in additicn to the isopolytungstic acids, with theheteropolytungstic acids wherein the central acid anhydride molecule isformed from an element of groups IV and V of the periodic table. Thus,the invention includes not only the isopolytungstates but also thesilicotungstates, the phosphotungstates, and the like. Because of theirgreater availability isopolytungstic and phosphotungstic acids arepreferred. Of these, the latter is available commercially and for thisreason, and also because it contributes slightly better thermalstability properties to the polymers and can be applied from slightlyless strongly acidic solution thereby causing less possible polymerhydrolysis, phosphotungstic acid is the most preferred polytungsticacid.

The poly-acid field is complex and is in a state of development. Theirspecific molecular structure and degree of hydration are therefore asyet not finally clarified. However, this specification uses thegenerally recognized mode of formulation of the isopolytungstic andheteropolytungstic acids, e. g., for isopolytungstic acid and for theheteropolyacids, wherein there are combined six to twelve W03 groups foreach anion of the parent acid, e. g.,

Inthe examples used to illustrate this invention the calculations arebased on the most generally accepted view that each molecule of thepolytungstic acids is bonded to three quaternary nitrogens in theformation of the quaternary ammonium polytungstate salts. However, theinvention is generic to quaternary ammonium polymers wherein from one tosix quaternary ammonium nitrogens are bonded to each polytungstateanion.

In those instances where one or two quarternary ammonium nitrogens ofthe polymer are bonded to each polytungstate anion, there will be acidichydrogens ionically bonded to the polytungstate anion. Typical suchanions are In those instances where three quaternary ammonium nitrogensof the polymer are bonded to each polytungstate anion, the anions willusually be in the so-called monomeric form, i. e., of the type. However,such anions may be in the socalled dimeric aggregate form, e. g.,

In those instances where four, five, or six quaternary nltrogens of thepolymer are bonded to each polytungstate anion, the said anions will bein the higher aggregate form wherein six acidic hydrogens are available,and depending upon how many quaternary nitrogens are ionically bonded tothe said anion, there may be two, one, or none of the acidic hydrogensionically bonded to the said anions, e. g.,

1;. g., acrylic, haloacrylic, and methacrylic acids,

esters, nitriles, and amides, e. g., acrylonitrile, butyl acrylate,methacrylic acid, alpha-chloroacrylic acid, the aminoalkyl acrylates, e.g., betadiethylaminoethyl methacrylate; vinyl and vinylidene halides, e.g., vinyl fluoride, vinylidene chloride; vinyl carboxylates, e. g.,vinyl acetate; vinyl aryls, e. g., styrene; and other vinyl derivatives,e. g., methyl vinyl ketones, vinylpyridines, vinyl isobutyl ethers andthe like. The polymers of the present invention can also contain, incombination, units of polymerizable compounds containing a plurality ofethylenic double bonds including those having conjugated double bondswhich are furthermore both terminal ethylenic double bonds such asbutadiene, 2-chlorobutadiene, and compounds containing two or moreethylenic double bonds which are isolated with respect to each other,including, for instance, the acrylic and substituted acrylic esters ofpolyhydric alcohols, e. g., ethylene glycol dimethacrylate;polymerizable compounds having one ethylenic group conjugated with acarboxylic group, e. g., diallyl maleate, and compounds which have noconjugation of the polymerizable ethylenic groups, e. g., divinylsuccinate. The preferred copolymers of this invention are thosecontaining in addition to the extralinear polytungstate units incombined form those addition polymerizable monomers having a singleterminal methylene group joined by an ethylenic double bond to itsneighboring carbon, i. e., compounds containing the terminal group CH2=CBecause of the excellent over-all film and fiber properties theyexhibit, the acrylonitrile/quaternary ammonium polytungstate copolymersand the preparation of such copolymers by the treatment withpolytungstates of films and fibers of acrylonitrile/quaternary ammoniumcopolymer salts of simple acids constitute the most preferred form ofthis invention. These copolymers will usually contain at least 85%combined acrylonitrile and at least 0.015% combined tungsten with theremainder of the copolymer being the combined quaternary ammoniumradical carrying the polytungstate and other combined additionpolymerizable monomers as described above, particularly those containingbasic groups. Although higher amounts of combined tungsten may bepresent, these preferred copolymers will seldom have more than about2.0% combined tungsten since above this level not much improvement inthermal resistivity is attained and such polymers obviously are moreexpensive. As is true of all the polymers of this invention the mostpreferred of these acrylonitrile/quaternary ammonium polytungstatecopolymers will contain from 0.05 to 1.0% and usually from 0.1 to 0.75%combined tungsten. As the amount of combined acrylonitrile is increased,e. g., to or the preferred acrylonitrile/quaternary ammoniumpolytungstates become more thermally insensitive.

The polymers of the present invention are usually most convenientlyprepared by treating with an aqueous solution of the desiredpolytungstic acid a polymer of the desired structure having extralinearquaternary ammonium nitrogen groups which are singly bonded ionically inmultiples of one to three to anions of the simple acids, including themono-, di-, and tribasic acids. The term simple acids is used as in theRules for Inorganic Nomenclature (J. Am. Chem. Soc. 63 889 et seq.(1941)) in contrast to the polyacids. Anion interchange by treatmentwith the aqueous solution of the polytungstic acid may be carried out attemperatures ranging from room temperature to C. for periods of timeranging from as short as thirty seconds to as long as twenty-four hoursor longer, and is in all instances preferably carried out at pHs in therange 0.1 to 3.0. When the treatment with aqueous solutions of thepolytungstic acids is carried out under pH conditions greater than 3.0and in some instances greater than 1.5, e. g., in the case of thesilicotungstic acids, the polymeric quaternary ammonium polytungstatesso formed are of varying composition, the structures of which are notknown, and do not in general exhibit the superior thermal resistivity ofthe polymeric quaternary ammonium polytungstates prepared in the lowerpH ranges. Although improvement in thermal resistivity is obtained evenat a pH above 1.5 with silicotungstic acid and even at pH above 3.0 forpolytungstic acids in general, depending upon the temperature and timeof treatment, varying proportions of the simple quaternary groups willbe converted to the desired polytungstate groups. Accordingly, thepolymers of this invention can contain in combined form extralinearammonium nitrogens which are singly ionically bonded to anions of thesimple acids. Complete conversion of all the starting simple anions tothe desired polytungstate anion can be achieved by using longer reactiontimes, more highly concentrated treating solutions, higher temperature,or, preferably, by carrying out the reaction in solution, i. e., byusing a solution of the polymer and a solution of the polytungstic acidinvolved, preferably in miscible or compatible solvents. The choice ofsolvents will vary with the nature of the polymer involved and willinclude for example, alcohols, halogenated hydrocarbons, aromatichydrocarbons, cyclic tetramethylene sulfone, dimethylformamide and thelike. Solvents for polytungstic acids include alcohols and ethers. Theaqueous solutions of the polytungstic acids can be obtained by simplydissolving the requisite polytungstic acid in sufficient water to obtainthe desired concentration which can be from 0.1% to 10% andeven higherand usually suitably adjusting the pH of the resultant solution. Toobtain the higher concentrations, it frequently is necessary to employthe alkali metal salts. Alternatively, the polytungstic acids desiredcan be prepared directly in the aqueous treating solution by simplydissolving the theoretical molar quantities, in the concentrationsdesired, of the soluble alkali metal or alkaline earth metal salts ofthe simple component acids involved in the molecular structure of thepolytungstic acid and suitably adjusting the pH of the solution. Forinstance, an aqueous solution of isopolytungstic acid can be prepared bydissolving in the weight concentration desired an alkali metal tungstateand adjusting the pH to 3.0 or below, preferably below 2.5. Similarly,an aqueous solution of phosphotungstic acid may be prepared bydissolving in the weight concentrations desired one molar proportion ofan alkali metal phosphate with twelve molar proportions of an alkalineearth metal tungstate and adjusting the pH to below 3.0, and preferablybelow 2.5.

The polymers and copolymers of this invention are useful in thepreparation of oriented shaped objects such as films or fibers,particularly the latter, which have excellent strength and waterresistance with good dye absorption properties, particularly with aciddyes. Furthermore, the polymers and copolymers of this invention haveextremely good stability under conditions of high temperature.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations are to be understoodtherefrom. The invention is not limited to the exact details shown anddescribed for obvious modifications will occur to those skilled in theart.

What is claimed is:

1.An addition polymer of at least 0.015% tungsten content, having awholly carbon polymer chain, and having recurring extralinear quaternaryammonium polytungstate units wherein the valences of the quaternaryammonium nitrogen not satisfied by the anion not connected to thepolymer chain are satisfied by hydrocarbon radicals free from aliphaticunsaturation.

2.1m addition polymer of at least 0.015% tungsten content, having awholly carbon polymer chain, and having recurring extralinear quaternaryammonium polytungstate units wherein the quaternary ammonium nitrogen isbonded to the polymer chain through a negative group, is bonded to thepolytungstate anion, and has its remaining valencies attached tohydrocarbon radicals, free from aliphatic unsaturation, all of whosefree valences are attached to the quaternary nitrogen.

3. An addition polymer having a wholly carbon polymer chain and of atleast 0.02% tungsten content having recurring units of two polymer chaincarbons to one of which is bonded a -(CO)mORN 5? group wherein R is adivalent hydrocarbon radical, m is a cardinal number not greater thanone, one of the free valences of the nitrogen is attached ionically to apolytungstate anion, and the remaining valences of the nitrogen aresatisfied by hydrocarbon radicals, free from aliphatic unsaturation, allof whose free valences are satisfied by the nitrogen.

4. An addition polymer having a wholly carbon polymer chain and of atleast 0.02% tungsten content having recurring units of two polymer chaincarbons to one of which is bonded an ORNf group wherein R is a divalenthydrocarbon radical, one of the free valences of the nitrogen isattached ionically to a polytungstate anion, and the remaining valencesof the nitrogen are satisfied by hydrocarbon radicals, free fromaliphatic unsaturation, all of whose free valences are satisfied by thenitrogen.

5. An addition polymer having a wholly carbon polymer chain and of atleast 0.02% tungsten content having recurring units of two polymer chaincarbons to one of which is bonded a COORN group wherein R is a, divalenthy drocarbon radical, one of the free valences of the nitrogen isattached ionically to a polytungstate anion, and the remaining valencesof the nitrogen are satisfied by hydrocarbon radicals, free fromaliphatic unsaturation, all of whose free valences are satisfied by thenitrogen.

6. An addition polymer having a wholly carbon polymer chain and of atleast 0.02% tungsten content having recurring units of two polymer chaincarbons to one of which is bonded, through pyridinium ring carbon, aquaternary pyridinium ring, the pyridinium nitrogen being bondedionically to a polytungstate anion, to pyridinium ring carbons and to amonovalent hydrocarbon radical, free from aliphatic unsatmation.

7. An addition polymer having a wholly car bon polymer chain and of atleast 0.02% tungsten content having recurring units of two polymer chaincarbons to one of which is bonded a -(CO)mOAlkNroup wherein Alk is asaturated divalent aliphatic hydrocarbon radical of at least two carbonsbetween the free valences, m is a cardinal number not greater than one,one of the free valences of the nitrogen is attached ionically to apolytungstate anion, and the remaining valences of the nitrogen aresatisfied by hydrocarbon radicals, free from aliphatic unsaturation, allof whose free valences are satisfied by the nitrogen.

8. An addition polymer having a wholly carbon polymer chain and of atleast 0.02% tungsten content having recurring units of two polymer chaincarbons to one of which is bonded an OAlkN-i group wherein Alk is asaturated divalent aliphatic hydrocarbon radical of at least two carbonsbetween the free valences, one of the free valences of the nitrogen isattached ionically to a polytungstate anion, and the remaining valencesoi the nitrogen are satisfied by hydrocarbon radicals, free fromaliphatic unsaturation, all of whose free valences are satisfied by thenitrogen.

9. An addition polymer having a wholly carbon polymer chain and of atleast 0.02% tungsten content having recurring units of two polymer chaincarbons to one of which is bonded, through pyridinium ring carbon, aquaternary pyridinium ring, the pyridinium nitrogen being bondedionically to a polytungstate anion, to pyridinium ring carbons and to analkyl radical.

10. An acrylonitrile copolymer having a wholly carbon polymer chain andof major acrylonitrile content containing at least 0.02% tungsten in theform of polymer units having extralinear quaternary ammoniumpolytungstate groups wherein the valences of the quaternary ammoniumnitrogen not satisfied by the anion nor connected to the polymer chainare satisfied by hydrocarbon radicals free from aliphatic unsaturation.

11. An acrylonitrile copolymer having a wholly carbon polymer chain andof major acrylonitrile content and containing at least 0.02% tungsten inthe form of recurring units of two polymer chain carbons to one of whichis bonded a (CO)mORN group wherein R is a divalent hydrocarbon radical,m is a cardinal number not greater than one, one of the free valences orthe nitrogen is attached ionically to a polytungstate anion, and theremaining valences of the nitrogen are satisfied by hydrocarbonradicals, free from aliphatic unsaturation, all of whose free valencesare satisfied by the nitrogen.

12. An acrylonitrile copolymer having a wholly carbon polymer chain andof major acrylonitrile content and containing at least 0.02% tungsten inthe form of recurring units of two polymer chain carbons to one of whichis bonded a --(CO)mOAlkN group wherein Alk is a saturated divalentaliphatic hydrocarbon radical of at least two carbons between the freevalences, m is a cardinal number not greater than one, one of the freevalences of the nitrogen is attached ionically to a polytungstate anion,and the remaining valences of the nitrogen are satisfied by hydrocarbonradicals, free from aliphatic unsaturation, all of whose free valencesare satisfied by the nitrogen.

13. A copolymer according to claim 12 wherein the polytungstate anion isa heteropolytungstate anion.

l l. An acrylonitrile copolymer having a wholly carbon polymer chain andof major acrylonitrile content and containing at least 0.02% tungsten inthe form of recurring units of two polymer chain carbons to one of whichis bonded an OAlkN; group wherein Alk is a saturated divalent aliphatichydrocarbon radical of at least two carbons between the free valences,one of the free valences of the nitrogen is attached ionically to apolytungstate anion, and the remaining valences of the nitrogen aresatisfied by hydrocarbon radicals, free from aliphatic unsaturation, allof Whose free valences are satisfied by the nitrogen.

15. An acrylonitrile copolymer having a wholly carbon polymer chain andof major acrylonitrile content and containing at least 0.02% tungsten inthe form of recurring units of two polymer chain carbons to one of whichis bonded, through pyridinium ring carbon, a quaternary pyridinium ring,the pyridinium nitrogen being bonded ionically to a polytungstate anion,to pyridinium carbons and to an alkyl radical.

16. A copolymer according to claim 15 wherein the polytungstate anion isa heteropolytungstate anion.

17. Process for improving the thermal stability of acrylonitrilepolymers having a wholly carbon polymer chain of major acrylonitrilecontent containing a minor proportion of polymer units having attachedto polymer chain carbons extralinear quaternary ammonium salt groupswherein the salt anion is that or" a simple acid and wherein thevalences of the quaternary ammonium nitrogen not satisfied by the anionnor connected to the polymer chain are satisfied by hydrocarbon radicalsfree from aliphatic unsaturation which process comprises bringing saidcopolymer in contact with an aqueous solution containing a polytungstateanion until at least 0.02%, by weight of the polymer, of tungsten isincorporated into the composition of the polymer.

18. The process of claim 17 wherein the polytungstate anion is aheteropolytungstate anion.

19. The process of claim 17 wherein the polytungstate anion is thephosphotungstate anion.

20. Process for improving the thermal stability of acrylonitrilepolymers having a wholly carbon polymer chain of major acrylonitrilecontent containing a minor proportion of units of two chain carbons toone of which is bonded a (CO)mOAlkN group wherein Alk is a saturateddivalent aliphatic hydrocarbon radical of at least two carbons betweenthe free valences, mis a cardinal number not greater than one, one ofthe free valences of the nitrogen is attached ionically to the anion ofa simple acid and the remaining valences of the nitrogen are satisfiedby hydrocarbon radicals, free from aliphatic unsaturation, all of whosefree valences are satisfied by the nitrogen, which process comprisesbringing said copolymer in contact with an aqueous solution containing apolytungstate anion until at least 0. 2%, by weight of the polymer, oftungsten is incorporated into the composition of the polymer.

21. Process for improving the thermal stability of acrylonitrilepolymers having a wholly carbon polymer chain of major acrylonitrilecontent containing a minor proportion of units of two chain carbons toone of which is bonded an OAlkN; group wherein Alk is a saturateddivalent aliphatic hydrocarbon radical of at least two carbons betweenthe free valences, one of the free valences of the nitrogen is attachedionically to the anion of a simple acid and the remaining valences ofthe nitrogen are satisfied by hydrocarbon radicals, free from aliphaticunsaturation, all of whose free valences are satisfied by the nitrogen,which process comprises bringing said copolymer in contact with anaqueous solution containing a polytungstate anion until at least 0.02%,by weight of the polymer, of tungsten is incorporated into thecomposition of the polymer.

22. Process for improving the thermal stability of acrylonitrilepolymers having a wholly carbon polymer chain of major acrylonitrilecontent containing a minor proportion of units of two chain carbons toone of which is bonded, through pyridinium ring carbon, a quaternarypyridiniu'm ring, the pyridinium nitrogen being bonded ionically to theanion of a simple acid and the remaining valences of the nitrogen aresatisfied by hydrocarbon radicals, free from aliphatic unsaturation, allof whose free valences are satisfied by the nitrogen, which processcomprises bringing said copolymer in contact with an aqueous solutioncontaining a polytungstate anion until at least 0.02%, by weight of thepolymer, of tungsten is incorporated into the composition of thepolymer.

23. Process for improving the thermal stability of an addition polymerhaving a wholly carbon polymer chain and having recurring extralinearquaternary ammonium salt groups wherein the anion is that of a simpleacid and wherein the valences of the quaternary ammonium nitrogen notsatisfied by the anion nor connected to the polymer chain are satisfiedby hydrocarbon radicals free from aliphatic unsaturation which processcomprises bringing said polymer in contact with an aqueous solutioncontaining a polytungstate anion until at least 0.02%, by weight of thepolymer, of tungsten is incorporated into the composition of thepolymer.

24. .An acrylonitrile copolymer having a. wholly carbon polymer chainand of major acrylonitrile content and containing at least 0.02%tungsten in the form of recurring units of two polymer chain carbons toone of which is bonded a COOAlkN group wherein All: is a saturateddivalent aliphatic hydrocarbon radical of at least two carbons betweenthe free valences, one of the free valences of the nitrogen is attachedionically to a polytungstate anion, and the remain ing valences of thenitrogen are satisfied by hydrocarbon radicals, free from aliphaticunsaturation, all of whose free valences are satisfied by the nitrogen.

25. An acrylonitrile copolymer having a wholly carbon polymer chain, ofmajor acrylonitrile content, and containing at least 0.02% tungsten inthe form of recurring ,6-methacryly1oxyethyltrimethylammoniumphosphotungstate units.

26. An acrylonitrile copolymer having a wholly carbon polymer chain andof major acrylonitrile content and containing at least 0.02% tungsten inthe form of recurring 2--vinyloxyethyltrimethylammonium phosphotungstateunits.

2'7. An acrylonitrile copolymer having a wholly carbon polymer chain andof major acrylonitrile content and containing at least 0.02% tungsten inthe form of recurring 1,2-dimethyl-5-vinylpyridinium phosphotungstateunits.

References Cited in the file of this patent UNITED STATES PATENTS Number

1. AN ADDITION POLYMER OF AT LEAST 0.015% TUNGSTEN CONTENT, HAVING AWHOLLY CARBON POLYMER CHAIN, AND HAVING RECURRING EXTRALINEAR QUATERNARYAMMONIUM POLYTUNGSTATE UNITS WHEREIN THE VALENCES OF THE QUATERNARYAMMONIUM NITROGEN NOT SATISFIED BY THE ANION NOR CONNECTED TO THEPOLYMER CHAIN ARE SATISFIED BY HYDROCARBON RADICALS FREE FROM ALIPHATICUNSATURATION.